Project Gemini was the second human spaceflight program in which the United States of America sent humans into space during the years 1963-1966. Its objective was to develop techniques for advanced space travel. Gemini missions involved extravehicular activity and orbital maneuvers including rendezvous and docking. Gemini was originally seen as a simple extrapolation of the Mercury program, however, the final program had little in common with Mercury and was superior to even Apollo in some ways. The Gemini capsule could alter its own orbit. It could also dock with other spacecraft, one of which, the Agena Target Vehicle, had its own large rocket engine which was used to perform large orbital changes. Gemini was the first American manned spacecraft to include an onboard computer, it used ejection seats, in-flight radar and an artificial horizon. There were many proposals to expand on the Gemini program including missions to the Moon however none of these proposals were ever funded.